JP2005145683A - Antistatic conveying device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antistatic conveying device which prevents occurrence itself of static electricity between a conveyed object and a conveying body, does not require special measures for preventing occurrence of static electricity or special measures for rapidly releasing the occurring static electricity, and can suppress drop of yield caused by the static electricity. <P>SOLUTION: In the antistatic conveying device, an insulating box 2 is made of PP material, and stores articles 1 having a built-in LSI. The conveying device 3 is provided with a roller conveyor 4 where static electricity suppressing rollers 5 are arranged in the conveying direction in a predetermined pitch to configure a conveying passage of the conveyed article. Each static electricity suppressing roller 5 has a base roller made of a steel pipe and a static electricity suppressing layer formed by winding on the base roller a conductive PE film having work function where the difference between it and work function of the insulating box 2 made of the PP material is within ±0.1 eV so as to cover the outer peripheral surface of the base roller. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an antistatic transport device that transports an article or a box to which an article has been delivered, for example, by a roller or a belt, and more particularly, to a work function of the article or a box to which the article has been delivered such as a roller or a belt. The present invention relates to an antistatic transport apparatus that regulates the size of a work function to prevent the generation of static electricity.

  When an article is conveyed by a roller conveyor, static electricity is likely to be generated due to contact friction between the roller member and the box to which the article material or article is delivered. The article described here is a plastic film, a plastic sheet, paper, a plate, a metal, an electronic device (such as an IC or an insulating substrate), an electronic electrical device, or the like. In recent years, there has been an increase in automatic conveyance equipment that conveys articles due to friction generated between an insulating substrate incorporating an LSI constituting an electronic device or an electrical device and a roller or belt. In such facilities, there is a possibility that surrounding dust is attracted to the article by static electricity generated by the article or a box to which the article is delivered and a roller or a belt, and the dust may adhere to the article. This causes a problem of lowering. Further, depending on the amount of static electricity charged in the article, a discharge occurs between the article and the outside. Thus, when the article is an electronic device, the LSI in the electronic device may be damaged by dielectric breakdown, resulting in a defective article. Therefore, taking measures to prevent the generation of static electricity or to quickly release the generated static electricity is extremely useful in improving the yield of articles.

  Based on the above-mentioned viewpoint, the charge control agent is kneaded into a rubber roller, a resin roller or the like so as to be in the same charged row as the material to be transported, or fixed to the surface, and the charge control agent is added. An antistatic method has been proposed that prevents the generation of static electricity on the surface of the material to be conveyed by covering the metal roller with a resin adjusted so as to have the same charge train as the material to be conveyed (for example, , See Patent Document 1). A conventional roller by this antistatic method is obtained by roughly crushing 66 nylon with a mixer, adding a charge control agent, spiron black, heating and compounding, and then forming into a roller shape.

JP 05-094895 A (paragraphs 0006, 0010)

  The conventional roller can prevent static electricity from being generated on the surface of the material to be conveyed. However, since the molded product is prepared from a compound and molded into a roller shape, there is a problem that it takes time and effort to manufacture. In the conventional antistatic method, the charge control agent-added resin is coated so as to be in the same charge train as the material to be conveyed, but the charge train is only a qualitative order, and the measurement state of the measurer and Since the measurement result may vary greatly depending on the purity of the target material, there is no guarantee that the charged train described in the literature is correct. In particular, the amount of static electricity generated is likely to change by adding a small amount of additives to the main material, and the charged train cannot be said to be a physical property value based on scientific grounds. In addition, the roller coated with the charge control agent-added resin has a problem that the charge control agent-added resin layer is exposed on the surface and the additive resin layer is worn out in a short period of time, so that the effect of preventing static electricity cannot be obtained. It was.

  Furthermore, other static electricity suppression measures include installation of static eliminators (ionizers) at many locations. Ionizers are commercially available from static eliminators, and installing an ionizer can be considered as a general measure. However, in some cases, the installation environment of the transfer device may be an outdoor environment with a lot of dust. In such an environment, the discharge needle of the ionizer is contaminated, and the static elimination efficiency immediately deteriorates. Accordingly, there is a problem that daily maintenance and installation of a large number of ionizers are necessary, which increases installation and maintenance costs.

  Accordingly, there has been a demand for a measure that eliminates the need for installing a large number of devices such as ionizers and maintains the antistatic effect for a long period of time. An object of the present invention is to solve such problems, and it is possible to stably prevent the generation of static electricity for a long period of time with a simple device.

  According to this invention, the antistatic transport device transports the transported object by friction generated between the transported object and the transported body, and the transport body is at least a surface layer in contact with the transported object Are configured to have substantially the same work function as the material of the part of the object to be contacted.

  According to the present invention, generation of static electricity between the transported object and the transport body is prevented, and without taking special measures to prevent the generation of static electricity or special measures to quickly release the generated static electricity. In addition, it is possible to suppress a decrease in yield due to static electricity.

  First, before describing embodiments, in order to clarify the technical significance of the present invention, the principle of generation of static electricity between members in contact with each other, the necessity to suppress the generation of static electricity, and between members in contact with each other The dependence of the amount of static electricity generated between members on the work function difference will be described.

  In order to prevent the generation of static electricity, it is necessary to pay attention to the material of the roller member, the belt member, etc. (conveyance body) that comes into contact with the article at the time of conveyance, or the box to which the article is delivered (conveyed object). . That is, charging caused by peeling between two substances A and B (hereinafter simply referred to as “peeling charging”), charging caused by friction between substances A and B (hereinafter simply referred to as “friction charging”), etc. Static electricity is a phenomenon that occurs when substances A and B having different electrical characteristics come into contact with each other, and can be interpreted as follows.

  First, in the exfoliation charging, when the substances A and B are in close contact, for example, a negative charge moves from the substance A to the substance B, the substance A is charged with positive electricity (static electricity), and the substance B is negative. Take on the electricity (static electricity). However, since the substances A and B are in close contact with each other at this time, the capacitance between the substances A and B is extremely large, and the potential is hardly observed. Thereafter, when the substance A charged with positive electricity (static electricity) and the substance B charged with negative electricity (static electricity) are separated (separated) and a distance is generated, the electrostatic capacity between the substances A and B is finite. Value. Therefore, a potential is generated between the substances A and B, and the charging phenomenon of the substances A and B is observed from the outside. As described above, the charging phenomenon is observed only by the operation of peeling, and the charging phenomenon occurs while the substances A and B are in contact with each other.

  Next, friction charging will be described. If the contact interface between the substances A and B is viewed microscopically, the surfaces of the substances A and B have irregularities, and the substances A and B are in partial contact with each other according to the shape of the irregularities. By performing the operation of friction in the contacted state, the portion of contact between the substances A and B increases. As a result, the charges moving between the substances A and B increase, and the charge amounts of the substances A and B increase. Therefore, frictional charging is also caused by the direct contact between the substances A and B.

  It can be considered that the static electricity generated by these peeling charging and frictional charging is basically a phenomenon caused by contact between two substances A and B having different electrical characteristics. In order to prevent defects due to static electricity, there are a method for preventing the generation of static electricity and a method for releasing the generated static electricity. In the latter case, grounding is performed on the article in the transporting process, the box containing the article, or the roller member that is in contact with the article, and a means for releasing the charge to the grounding point is taken. Also, as an effect of grounding, the apparent potential is reduced. That is, if the distance from the ground to the article or the box containing the article is short, the capacitance increases, and the potential of the article or the box containing the article decreases. Accordingly, it is possible to prevent static electricity failure such as discharge on the article or the box containing the article. However, it is possible to remove the charge made on the article made of metal and the roller member side by this measure, and the charge made on the insulation box to which the article is delivered or the article made of the insulator cannot be removed. Therefore, static electricity is generated and accumulated in the insulating article or the insulating box containing the article. Therefore, in order to prevent defects due to static electricity, it is necessary to suppress the generation of static electricity that is the basis. The present invention has focused on this point.

  First, an example of generation of static electricity and a defect of an article in a conveyance process (conveyance process) will be described with a conveyance system using rollers. The outline is shown in FIG. For example, an article 1 containing an LSI is placed in an insulating box 2 and conveyed to the next process. At that time, static electricity is generated between the roller member surface and the back surface of the insulating box 2. As described above, this occurs due to contact triboelectric charging caused by contact between substances A and B having different electrical characteristics. In FIG. 10, for example, the insulating box 2 is negatively charged. Since the roller 21 is grounded with metal, the electric charge escapes immediately. The static electricity generated in the insulating box 2 in this state causes an electrostatic induction phenomenon in the article 1, and when the article 1 charged to the same level as the insulating box 2 is brought into contact with the ground or a human body, electrostatic discharge occurs, and the article 1 There is a possibility that the insulation film in the built-in LSI will cause dielectric breakdown.

  In order to prevent the generation of static electricity, it is necessary to take measures to prevent electric charges from being generated between the insulating box 2 and the roller 21. For this purpose, a transfer device is proposed in which the roller material is changed to a charge suppression material and static electricity is not generated in the insulating box 2. This countermeasure does not cause static electricity defects of the article 1. First, in order to clarify the mechanism of static electricity generation in the transport process (transport process), a basic experiment was conducted and the results are reported.

As a basic experiment, the potential of a roller conveyor provided with rollers wound with various film materials and an insulating box transported thereon was measured. The conveyance conditions in various film materials are the same. The insulating box is made of polypropylene (PP). For the film material wound around the roller, five types of conductive polyethylene (conductive PE), insulating polyethylene (insulating PE), polytetrafluoroethylene (PTFE), polyethylene terephthalate (PET), and 66 nylon (nylon) are used. It was. For comparison, measurement was also performed using a steel pipe (carbon steel pipe for mechanical structure: STKM13A) that is generally used as a transport roller. FIG. 11 shows the surface potential of the insulating box after being conveyed using these roller materials. In FIG. 11, the surface potentials of the two times when the insulating box and the roller material are brought into contact with each other are plotted, and the white square indicates the average value.
From this result, it was confirmed that the steel pipe roller was charged to about −1 kV, whereas the characteristics of the roller wound with various film materials were greatly different. That is, in insulating PE and PTFE, the insulating box is positively charged, whereas in nylon and PET, it is negatively charged. Note that the conductive PE had the lowest potential within −0.1 kV.

As described above, although the amount of static electricity generated varies depending on the material, the electrostatic charging mechanism of the insulator is still under investigation and has not been clarified. As a general report, it is said that the generation of static electricity varies depending on the combination of materials and is determined by the charged train. The charge column is a relative order of various substances that are easily charged positively or easily charged negatively, and an example is shown in FIG. It is said that the amount of generation of static electricity is lower as the combination of those located closer to each other in the charged column is lower.
However, in the charge train, the insulating PP and the insulating PE are close to each other, and it is expected that the amount of static electricity generated is small when these materials are in contact. However, as shown in FIG. 11, in an actual measurement, a high potential is generated even though an insulating box made of an insulating PP material contacts the insulating PE. Thus, it is not always possible to suppress the amount of static electricity generated by a combination of those close to each other in the charged column. Furthermore, it can be seen that the charged series varies greatly depending on the purity of the material and the measurement environment, and the order of the materials differs depending on the report, and is only a relative order. Therefore, it is only a qualitative view to obtain the amount of static electricity generated by a combination of those close to each other in the charged column, and the scientific basis is poor. By the way, the description of the charged column for the conductive PE is not shown in any literature.

From this point of view, even if the material of the roller in contact with the article or the box to which the article is delivered is changed in the transport process, in order for antistatic to be established, the article or the box to which the article has been delivered. It is necessary to clarify the contact frictional charging phenomenon with the roller material.
Here, the difference in the charge amount of the insulating box due to the difference in the work function (work function value) of the film material used for the roller will be described. FIG. 13 is a graph showing the correlation between the surface potential of the insulating box (from the results of FIG. 11) and the work functions of various materials when various materials are used for the rollers. The vertical axis represents the surface potential (kV (kilovolt)) as the charge amount of the insulating box, and the horizontal axis represents the work function (eV (electron volts)) of various materials. In FIG. 13, all the two potentials where the insulating box and the roller material are brought into contact are plotted with black circles, and the white squares indicate average values. The work function of the insulating box (PP material) itself is 4.9 eV and is shown in the figure. From FIG. 13, it can be confirmed that the work function and the surface potential of the insulating box increase around the work function of the insulating box (PP: work function is 4.9 eV).
The work function is physically the energy required to raise the electron with the highest energy among the electrons in equilibrium in the solid to the energy of the electron stationary in the vacuum. .

As shown in FIG. 13, the reason why the potential of the insulating box varies depending on the material in contact can be explained by the difference in the work function of the roller material. That is, when two different substances are brought into contact with each other, charges are easily transferred from one substance to another by the difference in work function, that is, charging at the time of contact is likely to occur. On the other hand, when two substances having close work functions are brought into contact with each other, the amount of charge movement is small, that is, it is difficult to be charged. The work function of an insulating box made of PP is 4.9 eV. As shown in FIG. 13, it can be seen that it is more difficult to charge the conductive PE material having the same work function as that of the insulating box.
Further, in FIG. 13, the work function of the insulation box is 4.9 eV, whereas the work function of nylon is 3.7 eV, the work function of PET is 4.4 eV, the work function of PE is 5.1 eV, and the work function of PTFE. The work function is 5.4 eV. When the roller material with a work function smaller than the work function of the insulating box is contacted, the insulating box is negatively charged. When the roller material has a work function larger than the work function of the insulating box, the insulating box is charged. Is positively charged. It can be seen that the larger the work function difference between the contact materials, the greater the absolute charge amount. At this time, for example, the smaller the difference between the work function of the insulating box and the work function of the roller material, the more the charge generation can be suppressed. In this transfer device (transfer process), dielectric breakdown of the insulating film of the LSI occurs at about 500 V or more, so it is necessary to manage it within 500 V. From FIG. 13, the work within ± 0.1 eV with respect to the work function of the insulation box It is desirable to use a material having a function.

  Next, a method for measuring the work function of the roller material will be described. A conductive material (metal) or the like can be measured with a photoelectron spectroscopy apparatus. However, the work function of the insulating material applied to the roller material is rarely reported in the literature, and the insulating material differs depending on the additive and the like rather than the main material component. Therefore, it is necessary to measure the material tested this time. As the method, each metal member having a known work function is contact-peeled to an insulating material applied to the roller material. By measuring the amount of generated charges thereafter, the equivalent method was used.

The case where aluminum (Al), nickel (Ni), and gold (Au) are respectively used for the metal member having a known work function will be specifically described.
First, charging is performed by contact-peeling an insulating box material as a material to be measured or a material used for a roller material on three types of metal members having a known work function.
Next, a calibration curve representing the relationship of the charging potential to the known work function of a metal member as shown in FIG. 14 is obtained by measuring the charging potential of three insulating box materials or roller materials with three surface potentiometer probes. Create In FIG. 14, the black circles represent all measured plots, and the plots represented by white squares represent average values.
FIG. 14 shows a calibration curve when an insulating box material or a roller material is used as the material to be measured. As described above, as the metal member, aluminum (Al: work function 4.19 eV), nickel ( Three types of metals, Ni: work function 4.68 eV) and gold (Au: work function 4.90 eV) are used. Note that these work functions are measured values by photoelectron spectroscopy.
Next, the work function when the charging potential on the calibration curve shown in FIG. 14 is 0 V is obtained as the work function of the insulating box material or roller material. The work function of PP insulation box is 4.9 eV, whereas the work function of nylon, which is a roller material, is 3.7 eV, the work function of PET is 4.4 eV, the work function of PE is 5.1 eV, the work of PTFE The function is 5.4 eV. The work function of the conductive PE is a value measured by photoelectron spectroscopy and is 4.9 eV.

  For this reason, in order to prevent the generation of static electricity during the transportation process, in the apparatus for transporting the article or the box to which the article has been delivered, the article or the box to which the article has been delivered and the roller conveyor to be transported Thus, it is most preferable to use a material having a work function equal to that of the article or the box to which the article is delivered as the material of the roller to be contacted. However, in order to prevent dielectric breakdown of the insulating film of the LSI, it is necessary to manage it within 500 V. Therefore, a material having a work function within ± 0.1 eV with respect to the work function of the article to be contacted or the insulating box is used. What is necessary is just to use for roller material. By selecting the material of the roller material that contacts the article or the box to which the article is delivered based on the work function based on such conditions, the article or the box to which the article is delivered and the article or article It is possible to prevent the occurrence of static electricity between the roller material coming into contact with the delivered box. At the same time, since no static electricity is generated, there is no need to consider releasing or eliminating the charge generated in the article or the box to which the article is delivered, and it is not necessary to take measures.

  In order to use the same work function, it is best to use the same material, but there are cases where it cannot be made the same due to various restrictions. The present invention aims to prevent or reduce charging even in such a case.

Embodiment 1 FIG.
FIG. 1 is a perspective view showing a state of conveying an article by an antistatic transport device according to Embodiment 1 of the present invention, and FIG. 2 is a cross-sectional view showing an electrostatic suppression roller in the antistatic transport device according to Embodiment 1 of the present invention. It is.
In FIG. 1 and FIG. 2, an insulating box 2 as a transported object is made of a PP material, and stores an article 1 containing, for example, an LSI. The conveyance device 3 includes a roller conveyor 4 in which static electricity suppression rollers 5 as a conveyance body are arranged at a predetermined pitch in the conveyance direction and constitute a conveyance path for a conveyance object. Each static suppression roller 5 includes a steel tube base roller 6 and an electrostatic suppression layer 7 formed by winding a conductive PE film around the base roller 6 so as to cover the outer surface of the base roller 6. . The roller conveyor 4 is disposed so as to convey the article 1 to the next process. A stopper 8 is disposed on the roller conveyor 4 so as to stop the article 1 at a standby position for the next process of the article 1.

Next, a method for transporting the article 1 using the transport device 3 will be described.
First, when the transport device 3 is driven, the static electricity suppression roller 5 is rotationally driven. Then, the insulating box 2 in which the article 1 is stored is placed on the roller conveyor 4. Thereby, the insulation box 2 moves on the roller conveyor 4 to the standby position for the next process by the rotation of the static electricity suppression roller 5. When the insulating box 2 reaches the standby position for the next process, it is stopped at the standby position by the stopper 8.

In the first embodiment, the insulating box 2 is made of PP material, and its work function is 4.9 eV. On the other hand, the static electricity suppression layer 7 in contact with the insulating box 2 is made of a conductive PE film, and its work function is 4.9 eV. Thus, since the insulating box 2 and the static electricity suppressing layer 7 of the static electricity suppressing roller 5 in contact with the insulating box 2 are made of a material having an equal work function, the roller conveyor 4 is not charged without charging the insulating box 2. The top can be transported. Therefore, it is possible to suppress a decrease in yield due to static electricity without taking special measures for preventing the generation of static electricity or taking special measures for quickly releasing the generated static electricity. In other words, depending on the amount of static electricity charged in the article 1, a discharge may occur between the article 1 and the outside, and LSI in the electronic device may be damaged due to dielectric breakdown, thereby preventing the article from becoming defective. And the yield can be improved.
Moreover, since the static electricity suppression layer 7 is formed by wrapping the conductive PE film around the base roller 6 so as to cover the outer surface of the base roller 6, even if the static electricity suppression layer 7 is deteriorated (ruptured) or contaminated, It is only necessary to replace the static electricity suppressing roller 5 in which the static electricity suppressing layer 7 is deteriorated or contaminated, and the maintenance of the roller conveyor 4 is facilitated.

  In the first embodiment, the static electricity suppressing layer 7 is formed by winding the conductive PE film around the base roller 6 so as to cover the outer surface of the base roller 6. Or, considering the corrosion and wear due to the environment, the thickness of the conductive PE film is preferably 0.2 μm or more. Therefore, if the thickness of the static electricity suppressing layer 7 (conductive PE film) is 0.2 μm or more, the steel pipe base roller 6 is not exposed due to corrosion or wear due to chemicals or the environment in a short period of time. The effect that the generation of static electricity can be prevented stably. If the steel pipe base roller 6 is exposed, the insulating box 2 and the base roller 6 come into contact with each other, and the insulating box 2 is charged.

In the first embodiment, the static electricity suppressing layer 7 of the static electricity suppressing roller 5 is made of a conductive PE material having a work function equal to the work function of the material for producing the insulating box 2. The material of the suppression layer 7 is not limited to a material (conductive PE material) having a work function equal to the work function of the material for producing the insulating box 2, and in order to prevent dielectric breakdown of the LSI insulating film. Since it is necessary to manage within 500 V, any material having a work function within ± 0.1 eV with respect to the work function of the material for producing the insulating box 2 may be used.
In the first embodiment, the static electricity suppressing layer 7 of the static electricity suppressing roller 5 may be grounded. In this case, the charge generated by the static electricity suppressing roller 5 itself can be leaked, and the effect of lowering the apparent potential of the insulating box 2 can be obtained.

Embodiment 2. FIG.
FIG. 3 is a cross-sectional view showing the static electricity suppressing roller in the antistatic transport apparatus according to Embodiment 2 of the present invention.
In FIG. 3, the static electricity suppressing roller 9 is made of a conductive PE material having the same work function (4.9 eV) as that of the insulating box 2.
The second embodiment is configured in the same manner as in the first embodiment except that the static electricity suppressing roller 9 is used instead of the static electricity suppressing roller 5.

Also in the second embodiment, since the static electricity suppressing roller 9 of the roller conveyor in contact with the insulating box 2 is made of a material having a work function equal to that of the insulating box 2, the same effect as in the first embodiment can be obtained. .
Further, in the second embodiment, since the entire static electricity suppressing roller 9 is made of a conductive PE material, the steel pipe base roller 6 is not exposed even if it is subjected to corrosion or wear due to chemicals or the environment. . Therefore, there is an effect that the generation of static electricity can be stably prevented for a long time.

In the second embodiment, the entire static electricity suppressing roller 9 is made of a conductive PE material having a work function equal to the work function of the material for producing the insulating box 2. The material is not limited to a material (conductive PE material) having a work function equal to the work function of the material for producing the insulating box 2, and within 500 V in order to prevent dielectric breakdown of the insulating film of the LSI. Since it is necessary to manage, any material having a work function within ± 0.1 eV with respect to the work function of the material for producing the insulating box 2 may be used.
In the second embodiment, the static electricity suppression roller 9 may be grounded. In this case, leakage of charge generated by the static electricity suppressing roller 9 itself is possible, and an effect of lowering the apparent potential of the insulating box 2 can be obtained.

  Here, in Embodiments 1 and 2 above, it is assumed that the insulating box 2 which is a transported object is made of PP material. However, if the material of the insulating box 2 is changed, the static electricity suppressing layer 7 or the static electricity suppressing roller. The material of 9 is also appropriately selected from materials having a work function within ± 0.1 eV with respect to the work function of the material for producing the insulating box. For example, when a non-alkali glass substrate (work function: 4.9 eV) is used as an object to be transported, copper (work function: 4.9 eV) is used as a material for the static electricity suppressing layer and the static electricity suppressing roller, and an acrylic containing a semiconductor IC. When a resin tray (work function: 4.3 eV) is used as a conveyed object, polyethylene terephthalate (work function: 4.2 eV) is used as a material for the static electricity suppressing layer and the static electricity suppressing roller, and a quartz glass wafer case ( When the work function is 4.9 eV), conductive polyethylene (work function: 4.9 eV) can be used as a material for the static electricity suppressing layer and the static electricity suppressing roller.

Embodiment 3 FIG.
FIG. 4 is a top view showing the static electricity suppressing roller in the antistatic transport apparatus according to Embodiment 3 of the present invention.
In FIG. 4, the static electricity suppression roller 10 as a conveyance body is provided with a base roller (not shown) made of a steel pipe and an static electricity suppression layer 11 formed so as to cover the outer surface of the base roller. The static electricity suppressing layer 11 includes a first static electricity suppressing layer 11a formed by winding a PET film and a second static electricity suppressing layer 11b formed by winding a PE film alternately without gaps in the axial direction of the base roller. It is arranged regularly. Then, the ratio of the area of the first static electricity suppression layer 11a in contact with the insulating box 2 and the area of the second static electricity suppression layer 11b is adjusted by the surface potential ratio of the calibration graph (FIG. 13) obtained by the experiment using the work function difference. doing.
The third embodiment is configured in the same manner as the first embodiment except that the static electricity suppressing roller 10 is used instead of the static electricity suppressing roller 5.

In the third embodiment, the static electricity suppressing layer 11 includes a first static electricity suppressing layer 11a formed by winding a PET film and a second static electricity suppressing layer 11b formed by winding a PE film in the axial direction of the base roller. Are alternately arranged without gaps. When PET material and PE material are used for the static electricity suppressing layer 11, the first static electricity suppressing layer 11a (PET material) is positively charged and the second static electricity suppressing layer 11b (PE material) is negatively charged from the calibration graph of FIG. The polarity is different. The ratio of the absolute values is 1st static electricity suppression layer 11a (PET material): 2nd static electricity suppression layer 11b (PE material) = 2: 3. Therefore, the first static electricity suppression layer 11a (PET material) is 3 in the area ratio in contact with the insulating box 2, and the second static electricity suppression layer 11b (PE material) is 2 (the area ratio of the roller is the first static electricity suppression layer). 11a (PET material): second static electricity suppressing layer 11b (PE material) = 3: 2).
As a result, the apparent work function of the entire static electricity suppressing layer 11 in contact with the insulating box 2 corresponds to a material equal to the work function of the insulating box 2.
Therefore, also in the third embodiment, when the insulating box 2 is transported by the roller conveyor, the insulating box 2 is not charged, and it is not necessary to consider releasing the generated charge or removing the charge.

Embodiment 4 FIG.
FIG. 5 is a top view showing the static electricity suppressing roller in the antistatic transport apparatus according to Embodiment 4 of the present invention.
In FIG. 5, the static electricity suppressing roller 12 as a transport body includes a steel pipe base roller (not shown) and a static electricity suppressing layer 13 formed so as to cover the outer surface of the base roller. The static electricity suppressing layer 13 is configured by regularly arranging the first static electricity suppressing layer 13a made of PET film and the second static electricity suppressing layer 11b made of PE film alternately in the circumferential direction of the base roller without a gap. ing. Then, the ratio of the area of the first static electricity suppression layer 13a in contact with the insulating box 2 and the area of the second static electricity suppression layer 13b is adjusted by the surface potential ratio of the calibration graph (FIG. 13) obtained by the experiment using the work function difference. doing.
The fourth embodiment is configured in the same manner as the third embodiment except that the static electricity suppressing roller 12 is used instead of the static electricity suppressing roller 10.

In this Embodiment 4, the static electricity suppression layer 13 arranges the 1st static electricity suppression layer 13a which consists of PET films, and the 2nd static electricity suppression layer 13b which consists of PE films alternately by the circumferential direction of a base roller, without a space | gap. It is configured. Also in the fourth embodiment, the first static electricity suppression layer 13a (PET material) is positively charged and the second static electricity suppression layer 13b (PE material) is negatively charged and the polarities are different from the calibration graph of FIG. The ratio of the absolute values is 1st static electricity suppression layer 13a (PET material): 2nd static electricity suppression layer 13b (PE material) = 2: 3. Therefore, the first static electricity suppression layer 13a (PET material) is 3 in the area ratio in contact with the insulating box 2, and the second static electricity suppression layer 13b (PE material) is 2 (the area ratio of the roller is the first static electricity suppression layer). 13a (PET material): second static electricity suppressing layer 13b (PE material) = 3: 2).
As a result, the apparent work function of the entire static electricity suppressing layer 13 in contact with the insulating box 2 corresponds to a material equal to the work function of the insulating box 2.
Therefore, also in the fourth embodiment, when the insulating box 2 is conveyed by the roller conveyor, the insulating box 2 is not charged, and it is not necessary to consider releasing the generated charge or removing the charge.

In Embodiments 3 and 4 described above, the static electricity suppression layers 11 and 13 are configured using regularly arranged films (PET and PE). However, the PET material and the PE material are irregular. The static electricity suppressing layer having a predetermined contact area ratio may be constituted by a mixed film or a coating material.
In the third and fourth embodiments, the static electricity suppressing layers 11 and 13 that are in contact with the insulating box 2 are made of a mixture of a PET material and a PE material. The material is not limited to a combination of a PET material and a PE material, and may be a combination of two or more materials selected from, for example, polytetrafluoroethylene, polyethylene, polypropylene, polyethylene terephthalate, nylon, and metal. In this case, the area ratio of the selected material is set so that the apparent work function of the entire static electricity suppressing layer in contact with the insulating box has a work function whose difference from the work function of the insulating box is within ± 0.1 eV. Will be adjusted.

Embodiment 5 FIG.
6 is a side view showing a main part of a roller conveyor in an antistatic transport apparatus according to Embodiment 5 of the present invention.
In FIG. 6, the roller conveyor 14 includes a first static electricity suppressing roller 15 and a second static electricity suppressing roller 17 as a conveying body. The first static electricity suppressing roller 15 includes a steel pipe base roller 6 and a first static electricity suppressing layer 16 formed by winding a PET film so as to cover the outer surface of the base roller 6. The second static electricity suppressing roller 17 includes a steel pipe base roller 6 and a second static electricity suppressing layer 18 formed by winding a PE film so as to cover the outer surface of the base roller 6. Then, the ratio of the area of the first static electricity suppressing layer 16 and the area of the second static electricity suppressing layer 18 that is in contact with the insulating box 2 is adjusted by the surface potential ratio of the calibration graph (FIG. 13) obtained by the experiment using the work function difference. doing.
The fifth embodiment is configured in the same manner as the third embodiment except that the first and second static electricity suppressing rollers 15 and 17 are used instead of the static electricity suppressing roller 10.

Also in the fifth embodiment, the first static electricity suppression layer 16 (PET material) is charged positively and the second static electricity suppression layer 18 (PE material) is negatively charged from the calibration graph of FIG. The ratio of the absolute values is the first static electricity suppressing layer 16 (PET material): the second static electricity suppressing layer 18 (PE material) = 2: 3. Therefore, the first static electricity suppression layer 16 (PET material) is 3 in the area ratio in contact with the insulating box 2 and the second static electricity suppression layer 18 (PE material) is 2 (the area ratio of the roller is the first static electricity suppression layer). 16 (PET material): the number of the first and second static electricity suppressing rollers 15 and 17 is adjusted so that the second static electricity suppressing layer 18 (PE material) = 3: 2). In other words, the roller conveyor 14 includes three first static electricity suppressing rollers 15 having a first static electricity suppressing layer 16 made of PET film and two second static electricity suppressing rollers having a second static electricity suppressing layer 18 made of PE film. 17 is configured by arranging roller rows alternately arranged in the conveying direction.
Thereby, the apparent work function of the first and second static electricity suppressing layers 16 and 18 in contact with the insulating box 2 corresponds to a material equal to the work function of the insulating box 2.
Therefore, also in the fifth embodiment, when the insulating box 2 is transported by the roller conveyor 14, the insulating box 2 is not charged, and it is not necessary to consider releasing the generated charge or removing the charge. .

  In the fifth embodiment, the first and second static electricity suppressing layers 16 and 18 of the first and second static electricity suppressing rollers 15 and 17 constituting the roller conveyor 14 are configured using a PET material and a PE material. Although the material constituting the first and second static electricity suppressing layers 16 and 18 of the first and second static electricity suppressing rollers 15 and 17 is not limited to a combination of a PET material and a PE material, For example, a combination of two or more materials selected from polytetrafluoroethylene, polyethylene, polypropylene, polyethylene terephthalate, nylon, and metal may be used. In this case, the area ratio of the selected material is adjusted so that the apparent work function of the entire static electricity suppressing layer in contact with the insulating box has a work function within ± 0.1 eV of the work function of the insulating box. Will do.

Embodiment 6 FIG.
FIG. 7 is a side view showing an article conveyance state by an antistatic conveyance apparatus according to Embodiment 6 of the present invention.
In FIG. 7, the transport device includes a roller conveyor 4 configured by arranging static electricity suppressing rollers 5 in the transport direction, and the insulating box 2 in which the article 1 is stored is stopped at a standby position for the next process. In addition, the insulation box 2 is placed and controlled so that the rotation of the static electricity suppressing roller 5 stops.
Other configurations are the same as those in the first embodiment.

In the sixth embodiment, the insulating box 2 moves on the roller conveyor 4 to the standby position for the next process by the rotation of the static electricity suppressing roller 5. When the insulating box 2 reaches the standby position for the next process, it is stopped at the standby position by the stopper 8. Therefore, the rotation of the static electricity suppressing roller 5 on which the insulating box 2 is placed is stopped.
Therefore, since there is no rotation of the static electricity suppressing roller 5 on which the standby insulating box 2 is mounted, the contact friction time and area with the insulating box 2 are reduced, and the accumulation of charges in the insulating box 5 does not occur. Accordingly, it is possible to suppress a decrease in yield due to static electricity without taking special measures for preventing the generation of static electricity or taking special measures for quickly releasing the generated static electricity.

  Even if the standby insulating box 2 is placed on a steel pipe roller, electric charges are generated by contact charging. Therefore, even if the roller on which the standby insulating box 2 is placed stops rotating. It is preferable to use the static electricity suppressing roller 5 described above.

Embodiment 7 FIG.
FIG. 8 is a side view showing an article conveyance state by the antistatic conveyance apparatus according to Embodiment 7 of the present invention.
In FIG. 8, the transport device includes a roller conveyor 4 configured by arranging static electricity suppressing rollers 5 in the transport direction, and the insulating box 2 in which the article 1 is stored is stopped at a standby position for the next process. In addition, a cylinder 19 is disposed as a lift mechanism for separating the standby insulating box 2 from the static electricity suppressing roller 5.
Other configurations are the same as those in the first embodiment.

In the seventh embodiment, the insulating box 2 moves on the roller conveyor 4 to the standby position for the next process by the rotation of the static electricity suppressing roller 5. When the insulating box 2 reaches the standby position for the next process, it is stopped at the standby position by the stopper 8. Therefore, the cylinder 19 is operated and the insulating box 2 is lifted away from the static electricity suppressing roller 5.
Therefore, since the standby insulating box 2 is not subjected to the rotation of the static electricity suppressing roller 5, the time and area for contact friction with the insulating box 5 are reduced, and no charge is accumulated in the insulating box 2. Accordingly, it is possible to suppress a decrease in yield due to static electricity without taking special measures for preventing the generation of static electricity or taking special measures for quickly releasing the generated static electricity.

  In Embodiment 7 described above, the cylinder 19 is used to lift the insulating box 2 away from the static electricity suppressing roller 5, but the lift mechanism is not limited to the cylinder 19, and the static electricity suppressing roller 5 and Any method can be used as long as the insulating box 2 can be lifted from the static electricity suppressing roller 5 with a lift that creates a gap between them and prevents friction.

  Here, in each of the above-described embodiments, all the rollers of the conveying device are described as being configured by static electricity suppressing rollers. Thus, it is the most preferable form that all the rollers of the conveying device are constituted by static electricity suppressing rollers. However, changing all the rollers to static electricity suppressing rollers increases the burden of cost, change time, and the like, and thus becomes a problem particularly in a line having a long transportation distance. In view of this, it is preferable to use a static electricity suppressing roller in a region of the roller conveyor where static electricity is likely to be generated and accumulated, or a part of the region that moves to the next process and waits.

Embodiment 8 FIG.
FIG. 9 is a side view showing an article conveyance state by the antistatic conveyance apparatus according to Embodiment 8 of the present invention.
In FIG. 9, the static electricity suppressing roller 5 is arranged in a region where it moves to and waits for the next process, and the steel pipe rollers 21 are arranged in the preceding stage to constitute a roller conveyor 20. Further, the static elimination brush 22 is disposed immediately before and in the region where the static electricity suppressing roller 5 is arranged, and the ionizer 23 is disposed in the arrangement region of the roller 21 in the preceding stage of the static electricity suppressing roller 5 arrangement region.

In the eighth embodiment, static electricity may be generated when the insulating box 2 is conveyed by the roller 21. Static electricity generated by the roller 21 is not removed when the roller 21 is transported on the static electricity suppressing roller 5. That is, the static electricity suppressing roller 5 does not generate new static electricity, but static electricity (charge) already accumulated in the insulating box 2 is not removed.
However, since the static elimination brush 22 is disposed immediately before the arrangement area of the static electricity suppression roller 5 and the ionizer 23 is provided in the arrangement area of the roller 21 in the previous stage of the static electricity suppression roller 5, it is conveyed by the roller 21. The charges generated at the time are removed by the static eliminating brush 22 and the ionizer 23 and then conveyed onto the static electricity suppressing roller 5. In addition, since the static elimination brush 22 is disposed in the arrangement region of the static electricity suppression roller 5, the charge transferred onto the static electricity suppression roller 5 is removed by the static elimination brush 22.
Therefore, even in the roller conveyor 20 in which the static electricity suppressing roller 5 is disposed only in a part of the area where the process proceeds to the next process and waits, the charge generated in the roller 21 is efficiently removed. A conveying device that can be applied to a line having a long transportation distance can be obtained without increasing the burden of changing time.

In each of the above-described embodiments, the insulating box 2 is used as an object to be transported. However, the same effect can be obtained when the article 1 is directly transported by a roller conveyor without using the insulating box 2. Is obtained.
In each of the above embodiments, a roller conveyor using a roller as a conveying member has been described. However, the present invention can provide the same effect when applied to a belt conveyor using a belt as a conveying member.

It is a perspective view which shows the conveyance state of the articles | goods by the antistatic conveyance apparatus which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the static electricity suppression roller in the antistatic conveyance apparatus which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the static electricity suppression roller in the antistatic conveyance apparatus which concerns on Embodiment 2 of this invention. It is a top view which shows the static electricity suppression roller in the antistatic conveyance apparatus which concerns on Embodiment 3 of this invention. It is a top view which shows the static electricity suppression roller in the antistatic conveyance apparatus which concerns on Embodiment 4 of this invention. It is a side view which shows the principal part of the roller conveyor in the antistatic conveyance apparatus which concerns on Embodiment 5 of this invention. It is a side view which shows the conveyance state of the articles | goods by the antistatic conveyance apparatus which concerns on Embodiment 6 of this invention. It is a side view which shows the conveyance state of the articles | goods by the antistatic conveyance apparatus which concerns on Embodiment 7 of this invention. It is a side view which shows the conveyance state of the articles | goods by the antistatic conveyance apparatus which concerns on Embodiment 8 of this invention. It is a figure explaining an example of the static electricity generation | occurrence | production in the conveyance process, and the malfunction of articles | goods by a roller conveyance system. It is explanatory drawing which shows the surface potential of the insulation box with respect to roller material. It is explanatory drawing which shows an example of a charging column. It is explanatory drawing which shows the relationship between the work function of various roller materials, and the surface potential of an insulation box. It is explanatory drawing which shows the work function of the various members calculated | required from the calibration curve by contact charging with a metal piece.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Article, 2 Insulation box, 3 Conveying device, 4, 14 Roller conveyor, 5, 9, 10, 12 Static suppression roller, 7, 11, 13 Static suppression layer, 15 1st static suppression roller, 17 2nd static suppression roller 19 cylinder (lift mechanism).

Claims (9)

An antistatic transport device that transports the transported object by friction generated between the transported object and the transported body,
The transport body uses a material whose surface layer in contact with the object to be transported is different from the material of the part of the object to be transported, and substantially the same work function as the material of the part of the object to be transported in contact It is comprised so that it may have. The antistatic conveyance apparatus characterized by the above-mentioned.   2. The antistatic transport device according to claim 1, wherein at least a surface layer of the transport body that contacts the transported object is made of conductive polyethylene.   2. The antistatic transport device according to claim 1, wherein at least a surface layer of the transport body that contacts the transported object is composed of a plurality of materials.   4. The antistatic transport device according to claim 3, wherein the plurality of materials are selected from polytetrafluoroethylene, polyethylene, polypropylene, polyethylene terephthalate, nylon, and metal.   The contact area ratio of the part of the transport body composed of each of the plurality of materials to the transported object is based on the ratio between the charged potential of each of the plurality of materials and the transported object. It is adjusted so that the difference between the work function of at least the surface layer in contact with the transported object of the transport body and the work function of the material of the transported object part in contact with the surface layer is within ± 0.1 eV. The antistatic transfer device according to claim 3 or 4, wherein the antistatic transfer device is provided.   The transport body is a roller in which at least a surface layer in contact with the transported object is composed of the plurality of materials, and the rollers are arranged in a transport direction to form a transport path for the transported object. The antistatic transport device according to claim 3, wherein the antistatic transport device is a non-static transport device.   The transport body is a roller of the same number as the number of the plurality of materials, each of which has at least a surface layer in contact with the object to be transported composed of a single material of the plurality of materials. 6. The antistatic transport apparatus according to claim 3, wherein the transport path of the transported object is configured by being alternately arranged in a transport direction.   2. The apparatus according to claim 1, wherein driving of the transporting body in contact with the transported object is stopped while the transported object is waiting for movement to the next process. Item 8. The antistatic transport device according to any one of Items 7.   8. A lift mechanism for separating the object to be conveyed from the carrier while the object is waiting for movement to the next process. The antistatic transport device according to Item.

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